Aircraft cargo box

ABSTRACT

A cargo box especially adapted for use in housing aircraft cargo, which box is made up of a base or pallet, sides, a top or cover, and ends, all of which may readily and expeditiously be assembled to provide a watertight box which is at once able to withstand relatively heavy gravity loads incident to operation of the aircraft while at the same time being extremely light for the result produced. The construction of the box is such that it may readily be knocked down upon arrival at a destination and reused.

United States Patent [56] References Cilled UNITED STATES PATENTS2,778,072 1/1957 Palisca 220/46UX 2,869,750 l/l959 Doerr.... 220/42,896,271 7/1959 Kloote 220/9(F)UX 2,907,492 10/1959 Robertson 220/812,920,781 l/l 960 Butcher 220/1.5X 3,259,264 7/1966 Best 220/9(F)X3,261,493 7/1966 Smith 220/4X Primary Examiner-George E. LowranceAttorney-Shenier & O'Connor ABSTRACT: A cargo box especially adapted foruse in housing aircraft cargo, which box is made up of a base or pallet,

sides, atop or cover, and ends, all of which may readily andexpeditiously be assembled to provide a watertight box which is at onceable to withstand relatively heavy gravity loads incident to operationof the aircraft while at the same time being extremely light for theresult produced. The construction of the box is such that it may readilybe knocked down upon arrival at a destination and reused.

I E I i l '46 g I l 4 56 5Z1 54 56: 30 J V 22 26 T 7 2o AIRCRAFT CARGOBOX BACKGROUND OF THE INVENTION Present-day requirements for stowage ofaircraft cargo require that a large number of items be handled as aunit. In order to facilitate this operation, it has been suggested thata relatively large container be provided for housing a plurality ofsmaller items or containers so as to make up a cargo unit which canefficiently be handled. These large containers of necessity must meetrelatively stringent requirements. They must be sufficiently strong soas to handle cargo having a relatively large aggregate weight. Inaddition, they must be so constructed as effectively to withstandgravity loads incident to operation of the aircraft. While no greatdifficulty would be involved in making a container which is sufficientlystrong to meet these requirements, another most important considerationis that the container be relatively light. None of the containers knownin the prior art successfully meet the inconsistent requirements ofstrength and low weight necessary to provide an effective aircraft cargobox.

In a particular instance it is required to produce a container with abase capable of being used as a bulk cargo pallet measuringapproximately 8 feet by 10 /2 feet. The container is required to be 8feet high. The container, including the pallet, must not weigh in excessof 600 pounds and yet must be capable of handling 7 tons of cargo. Whenfully loaded, the container must be able to withstand a vertical load inthe down direction of gs and a vertical load in the upward direction ofabout 3 gs. Fore and aft loads of 3 gs must be withstood. The maximumside load permissible is 1% gs. The box is required to be able to beused with an existing pallet weighing about 255 pounds. Considering themaximum unloaded weight of the container including the pallet, thereremains only around 345 pounds available for the top, sides and ends ofthe container, all of which must meet the requirements outlined above.

Not only is it necessary that the cargo box be strong and light but,also, it is highly desirable for efficient handling that it be able tobe erected and then knocked down in a simple and expeditious manner.Owing to the fact that in handling such a unit adverse weatherconditions are likely to be encountered, it should be watertight.Provision should also be made for securing the box in position withinthe aircraft to prevent shifting of the entire box.

It is likely in use of a large cargo container that a wall thereof mayat some time be damaged by puncturing or the like. Our constructionpermits a damaged part of the box to be replaced to eliminate the needfor replacing the entire box. Similarly, parts of one of our boxes areinterchangeable with those of another one of our boxes.

We have invented an aircraft cargo box which is strong enough towithstand the loads incidental to its use and yet which is light enoughto meet the stringent requirements of the industry. Our box is capableof handling a heavy cargo load. Our box moreover is watertight. It maybe assembled and disassembled in a rapid and expeditious manner. Theparts making up our box may be stacked for storage in a relatively smallspace.

SUMMARY OF THE INVENTION One object of our invention is to provide anaircraft cargo box which is strong enough to withstand the loadsincident to its use while at the same time being lighter than themaximum weight permitted by industry standards.

Another object of our invention is to provide an aircraft cargocontainer comprising a pallet base capable of handling heavy loads.

A further object of our invention is to provide an aircraft cargo boxwhich can readily and expeditiously be assembled and then knocked down.

Still another object of our invention is to provide an aircraft cargobox which is watertight.

Yet another object of our invention is to provide an aircraft cargo boxwhich can be disassembled for storage in a small space.

A still further object of our invention is to provide an aircraft cargobox, parts of which are readily replaceable and are interchangeable withparts of others of our boxes.

Other and further objects of our invention will appear from thefollowing description.

In general our invention contemplates the provision of an aircraft cargobox comprising a pallet, base, sides, ends and a cover, all of which mayreadily and expeditiously be assembled to form a box by virtue ofinterengageable elements on the peripheries of the members making up thebox. Associated with the interengageable elements are seals which renderthe box watertight when assembled. The sides, ends and cover of our boxare so constructed as to be extremely light while at the same time beingable to withstand gravity loads as required. Our box may readily beknocked down upon arrival at its destination.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings whichform part of the instant specification and which are to be read inconjunction therewith and in which like reference numerals are used toindicate like parts in the various views:

FIG. 1 is a perspective of our assembled aircraft cargo box viewed fromthe right corner thereof with parts broken away;

FIG. 2 is a vertical section through one side of our aircraft cargo boxtaken along the line 2-2 of FIG. 1 and drawn on an enlarged scale;

FIG. 3 is a vertical sectional view through one end of our aircraftcargo box taken along the line 3-3 of FIG. 1 and drawn on an enlargedscale;

FIG. 4 is a horizontal sectional view taken through one end of ouraircraft cargo box along the line 4-4 of FIG. 1 and drawn on an enlargedscale;

FIG. 5 is a fragmentary view of a corner of the outside of an end panelof our aircraft cargo box with the panel disassembled;

FIG. 6 is a fragmentary horizontal sectional view of a corner of ouraircraft cargo box adjacent the bottom of the box;

FIG. 7 is a fragmentary top plan view of the left rear corner of ouraircraft cargo box with the cover removed and with a part broken away;

FIG. 8 is a fragmentary view of the underside of the corner of the coverof our aircraft cargo box;

FIG. 9 is a fragmentary sectional view of a corner of the top of ouraircraft cargo box taken along the line 9-9 of FIG. 1 and drawn on anenlarged scale;

FIG. 10 is a fragmentary sectional view illustrating an alternate meansfor securing the top to the end or side panels of our aircraft cargobox; and

FIG. 11 is a fragmentary sectional view of an alternate means forsecuring a side or end panel of our aircraft cargo box to the pallet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1 of thedrawings, our aircraft cargo box, indicated generally by the referencecharacter 10, includes a base or pallet, indicated generally by thereference character 12, two sides, one of which is indicated generallyby the reference character 14, two ends, one of which is indicatedgenerally by the reference character 16, and a cover indicated generallyby the reference character 18.

Referring now to FIGS. 1 to 3, the pallet or base 12 in cludes a body 20formed of a suitable material such, for example, as plywood. We providethe upper and under surfaces of the central portion of the body 20 withrespective abrasion resistant coverings 22 and 24 which may be made ofany suitable material such, for example, as glass fiber cloth which hasbeen impregnated with a suitable resin, such as an epoxy resin or thelike. Alternatively to employing glass fiber cloth, we may use laminatedpaper impregnated with a suitable resin to form the skins 22 and 24.

Each of the side edges of the pallet 12 is provided with an extrudedaluminum edging member 26 so shaped as to provide an inwardly extendingtongue 28 and corresponding groove 30 extending along the sides andaround the corners for reasons which will be explained hereinafter. Eachof the end edges of the pallet 12 carries an aluminum extrusion 32 soformed as to provide an inwardly extending tongue 34 and a correspondinggroove 36. At each of the corners of the pallet 12 we provide aluminumcorner members 38 to complete the aluminum edging of the pallet 12.These comer members 38 may be attached to members 26 and 32 by anysuitable means such as by welding or the like. The pallet edges areformed with a channel 37 under the tongue 28 and extending around theentire pallet to receive a sealing gasket 39.

The pallet 12 is so constructed as to be able to handle up to seven tonsof cargo. Owing to the fact that it must handle this large load, itmakes up a relatively large part of the weight of the box 10. By way ofexample, pursuant to the example of one set of requirements outlinedabove, our pallet 12 may weigh as much as 255 pounds.

Each of the sides 14 of our box includes a body 40 which we make of anappropriately strong and relatively light material. The inner and outersurfaces of the body 40 carry respective abrasion resistant skins 42 and44. The body 40 may be made of a rigid low-density polyurethane orpolystyrene foam material. The skins 42 and 44 may be made of a materialsuch, for example, as a glass fiber fabric impregnated with a suitablethermosetting resin, such as an epoxy resin or a phenolic resin forexample. Alternatively to using a glass fabric, the skins 42 and 44 maybe made from a resin incorporating glass fibers.

We provide an extruded aluminum edging 46 running along the bottom ofeach of the sides 14 to points adjacent the corners of the box. Inmaking a side 14, for example, the unit may be molded with the edging 46and the upper edging, to be described hereinafter, forming parts of themold so as to be filled with the synthetic resin adapted to foam makingup the body 40. The skins 42 and 44 can then be applied and are extendeddownwardly over a portion of the edging 46 to which they are adhered byan impregnating adhesive.

We provide each of the sides 14 with inwardly directed recesses 48extending along the lower edge of the side. As will be apparent from thedescription given hereinafter, the recesses 48 permit the application ofdevices for holding the container securely in position on the deck of anaircraft or the like.

We form the lower ends of the members 46 below the the recesses 48 withoutwardly extending tongues 50 which are adapted to fit into the grooves30 of the extrusions 26 in a manner to be described. Each of theextrusions 46 has a recess 52 over the tongue 50 and extending along thelength of the extrusion. Lips 54 and 56 at the edges of the groovesretain a sealing gasket 58 in position within the groove. As will bedescribed in more detail hereinafter, the sealing gasket 58 engages theupper surface of the tongue 28 and the under surface of tongue 50engages the gasket 39 when the box is assembled.

An upper edge extrusion 60 runs along the top of each of the sides 14between points adjacent the corners of the box. We form the extrusion 60so as to provide a tongue 62 and corresponding groove 64. A channel 66having edge-retaining lips 68 similar to the lips 54 and 56 receives aportion of the gasket 58 which runs entirely around the periphery of theside as will be apparent from the description given hereinafter.

Referring now to FIGS. 1, 4 and 6, each end of each of the sides 14carries a vertically extending corner extrusion 70 of aluminum. Each ofthe extrusions 70 extends from a point adjacent the base upwardly to apoint near the top of the side. We form the edge of each of theextrusions near the ends of the box with a vertically extending,inwardly directed tongue 72 and corresponding groove 74. A verticallyextending channel 76 in each extrusion 70 under the tongue 72 receives aportion of the side sealing gasket 58.

We provide the sides 14 with feet 78 at each corner below the cornerextrusions 70. Each of the feet 78 includes a flange 80 extendingoutwardly and welded to the underside of the corresponding cornerextrusion 70 and to the side extrusion 46. We provide the foot 78 with achannel 82 forming a continuation of channel 76 and leading to a curvedchannel 86 extending back to the channel 52. A tongue 84 on the footprovides a continuation of the tongue 72.

Referring now to FIGS. 1, 7 and 9, we provide the top of each cornerextrusion 70 with an opening 90 which connects channel 76 in thevertical edge of the side with a curved channel 92 leading into theupper edge channel 66. A curved tongue 94 forms a continuation of tongue62 around the corner. Gasket 58 comes up through opening 90 aroundchannel 92 and into channel 66.

From the structure just described, it will be apparent that the sealinggasket 58 associated with a side 14 extends entirely around theperiphery of the side. Its path may readily be traced as follows:Beginning with the upper channel 66 in the extrusion 60, the gaskettravels along the top of the side to one of the corner top pieces 90. Itruns along the arcuate channel 92 and down through opening 90 into thecorresponding vertical channel 76. At the foot 78 it runs through theextension 82 of the channel 76 and then into and through the arcuatechannel 86 which leads into the channel 52 in the extrusion 46. Gasket58 runs along that channel and through the other foot channel 86 of thatside 14, thence upwardly through the channel 76 and through an opening90 and channel 92 back to the channel 66. As will be apparent from thedescription hereinafter, when our box is assembled gasket 58 provides aseal around the entire periphery of the side 14.

Referring now to FIGS. 1 and 3 to 6, each of the end panels 16 has alower extrusion 96 similar in shape to the lower extrusion 46 of a side14. We form extrusion 96 with a foot or tongue 98 at the base thereofwhich is adapted to cooperate with the tongue 34 of the pallet extrusion32. Extrusion 96 has a channel 100 located above the tongue 98 andhaving retaining lips for holding a portion of the end panel gasket 102.

Each of the end panels includes an upper extrusion 104 of aluminum whichis similar in configuration to the side upper extrusions 60. We providethe upper extrusion 104 with an outwardly extending tongue 106 andcorresponding groove 108 as well as with a channel 110 which receivesand retains a portion of the gasket 102. It is to be understood ofcourse that we form each of the end panels 16 in a manner similar and ofthe same materials as are used to make the sides 14. That is, the body112 of the end is made of foamed plastic and is provide with skins 114and 116 which resist abrasion and which extend over portions of thealuminum extrusions 96 and 104. The gaskets 58, as well as the gaskets102, are made of any suitable material such, for example, as natural orsynthetic rubber.

The end panels 16 include respective vertically extending extrusions 118extending along the vertical edges of the ends. Each extrusion 118 isformed with a tongue 120 and with a corresponding groove 122 forcooperation with the tongue and groove 72 and 74 of a corner extrusion70 and the continuations thereof provided by feet 78. Verticallyextending channels 124 in the extrusions 118 receive and retain portionsof the end gasket 102.

Referring now to FIG. 5, adjacent the top of the end members theextrusions 118 and 104 are joined with a mitered butt joint and weldedtogether as indicated by the line 136. At the upper corners of the endsin order that the gasket 102 will provide a continuous seal, we cut thegasket at a 45 angle and join the cut ends with a suitable adhesive toform the gasket corner 138. We perform a similar operation at each pointat which the gasket is required to make a right angle bend.

Referring to FIGS. 1 to 3, 8 and 9, the cover 18 of our box includes abody having inner and outer skins 142 and 144 formed in the same manneras are the sides and ends of the box. We provide the cover or top withextrusions 146 extending along the sides of the top and with extrusions148 extending along the ends of the top, as well as with corner members,

indicated generally by the reference character 150. Each of the sideextrusions 146 is provided with a tongue 152 and corresponding grooves154. Channels 166 receive the cover gasket 158.

We provide each of the extrusions 148 with an inwardly directed tongue170 and groove 172 for cooperation with tongue 106 and groove 108.Channels 174 in the extrusions 148 receive the portions of gasket 158extending along the sides of the box.

Each corner member 150 has a curved, inwardly directed tongue 162 andcorresponding groove 164 for cooperation with tongue 91 and groove 93. Acurved channel 166 receives the cover gasket 158 in the region of thecorner of the box. We weld or otherwise secure member 150 to members 146and 148.

As an alternative to the side, end and top panel construction describedhereinabove, we may form the skins of thin sheets of synthetic resinreinforced with glass fiber filaments. Another alternative is to formthe panels of the box by riveting or welding aluminum, magnesium orother light metal sheets to the extrusions forming the skins for eachpanel. In this particular embodiment, we employ core material which is a2 pound density polyurethane foam, foamed in place between the skins.

Referring to FIG. 1, in order to hold the end panel 16 securely in placewhen the box is assembled in a manner to be described hereinbelow, weprovide each of the end panels with a plurality of pivoted dogs 176adapted to be rotated to engage strikes 178 on the corners of the sidepanels when the end panels are in place. The construction of the dogsand strikes is such as will cam the end panels firmly in placeeffectively to seal the cooperating tongues and gaskets.

Preferably we provide an arrangement for tying down cargo such as isrepresented by the block 180 in FIG. 1. For this purpose we arrange anet 182 of any suitable type known to the art over the cargo 180 andprovide it with tie-down straps 184, the free ends of which areadjustably received in D-rings 188 carried by a length of webbing 190attached to a retainer 192 in the pallet along the sides thereof. Aswill be described hereinafter, tension-releasable hooks, includingseparable parts 194 and 196, are used to suspend the net from the topbefore cargo is loaded into the box. For example, the element 194 may besecured in the top and the hook element 196 releasably engaged in theelement 194.

We provide each side of the box with a plurality of access openings 198through which the free ends of the tie-down straps 184 extend before thenet 182 is drawn down over the cargo. Doors 200 are adapted to closeover the openings 198 and can be latched in place by suitable dogs orlatches 202. We provide gaskets around the openings 198 to maintain thewatertight integrity of our container.

In use of our container when it is to be packed prior to being loadedonto the aircraft, the sides 14 first are erected on the pallet 12 andthe cover 18 is assembled on the sides. When this has been done, therear end panel is assembled from inside the box and is locked in placeby use of dogs 176 or the like.

Next, the net 182 is suspended from the top 18 by means of thetension-releasable hooks 196. The free ends of the tiedown straps 184are threaded through the D-rings 188 and are extended out through accessopenings 198. The box is now ready to be loaded with cargo. It is to benoted that we do not provide any retaining elements 192 along the endsof the pa]- let 12 so as not to interfere with loading of cargo fromeither end of the box. 162 When the box has been loaded, the remainingend panel 16 is assembled on the box. This can be achieved by standingthe end panel bottom on the edge of the pallet leading with the righttop comer into the box until stopped by the side and top panels. Thenwith a relatively small force, the top is moved about one-half inch tothe left to move the left top corner inside the box. The end panel thenis lifted slightly and drawn into place to engage the correspondingtongues and grooves of the end panel and of the pallet side panels andtop. The dogs 176 are then operated firmly to secure this end panel inplace. If desired, suitable keyoperated locks can be provided.

As an alternative to the construction of the end panels described above,we might put the end locking edge or tongue of the top panel on a hingeextending all the way along the end of the top. This could then be swungup to permit the end panel to be moved into place and then returned to aposition at which it engages the end panel. Suitable locks and seals ofcourse would be provided.

On arrival at its destination, the box can be unloaded by reversing theabove procedure and, if desired, the box may be completely knocked downand stored in a relatively small space.

It will be seen that as our box is assembled, the pairs of cooperatingtongues engage gaskets to provide double seals around the entireperipheries of all members. Thus, we effectively seal the interior ofthe container against entry of moisture. If desired, we might alsoprovide a pressure relief device 204 in one of the walls of the boxwhich might be of the type which is air permeable but moistureimpermeable, such as is shown in U. U.S. Pat. No. 3,072,285.

Referring to FIG. 10, we have shown an alternate way of securing the top18 to the front end panel 16, for example. In this form of our inventionwe provide an extrusion 206 running along the front edge of the top 18.Extrusion 206 is provided with an inwardly and downwardly extending,generally arcuate slot 208 running along the front edge of the top. Theunderside of the extrusion 206 is provided with a channel 210 forreceiving a portion of the gasket 158. With the exception of theextrusion, the construction of the top panel 18 is generally similar tothat described hereinabove.

In the form of our invention shown in FIG. 10 we provide the front endpanel 16 with a top extrusion 212 having a generally circular recess 214therein which provides a bearing surface for a shaft portion 216 of anextrusion having an arm 218 provided with a curved hook 220 adapted toride into the recess 208. A handle portion 222 permits the hook to beextracted when desired. A channel 224 receives a portion of the gasket102.

Referring now to FIG. 11, as an alternative to the double tongue andgroove arrangement described hereinabove for joining the side and endpanels to the pallet, we may provide the side panel 14, for example,with an extrusion 226, the bottom edge of which is formed with agenerally arcuate tongue or hook 228 and with a channel 230 forreceiving a portion of the gasket 58. The pallet 12 in this form of ourcargo box is provided with an extrusion 232 along the edge thereof,which extrusion has an elongated generally arcuate slot or groove 234for receiving the tongue or hook 228. We provide the extrusion 232 witha channel 236 for receiving the gasket 39. It will readily beappreciated that we could provide the pallet extrusions with the tonguesor hooks 228 and provide the lower edges of the end and side panels withgrooves 234.

In another preferred embodiment of our cargo box we provide the pallet12 with the peripheral generally arcuate groove or slot 234 and providethe side and end panels with hooks 228 for insertion in the groove 234.One of the end panels is connected to the top and to the side panels bythe double tongue and groove method. We connect the other end panel tothe top and to the side panels by use of the pivoted hook groove methodshown in FIG. 10. With this construction the container may be opened bydisengaging the hooks of the end panel from the side panels and top,tilting the panel outwardly and removing it. The full end opening isthen available for access to the box interior.

In a further preferred embodiment of our box we provide the pallet withperipheral hooks 228 and form the lower edge extrusions of the side andend panels with grooves 234 for receiving the hooks. We then use thepivoted hook and groove arrangement shown in FIG. 10 to join the endpanels to the side panels and to the top. This arrangement has theadvantage of permitting removal first of' any one of the top or end orside panels. Thus the contents can be removed in any order, dependingupon which member of the box is removed first.

In all forms of our cargo box with the box assembled, the interengagedconnecting means prevent the top panel from being lifted by internalforces when the plane descends and also cause the top panel to absorbstresses caused by the side or end panels when the plane accelerates ordecelerates so as to result in internal forces on the side or endpanels. When the parts are thus assembled, the gaskets provide seals asdescribed.

While we have shown the form of our invention in FIG. 10 as being usedonly to join the upper edge of the front end panel 16 to the front edgeof the top 18, it will readily be appreciated that we may use thisarrangement around the entire periphery of the top. We may, moreover,use this arrangement along vertical edges of the side and end panels.Alternatively, it can used in combination with the tongue and groovearrangements heretofore described. It has the advantage of permittingthe front end panel to be swung outwardly rather than being pushedinwardly when the box is to be unloaded.

In all boxes of the type known in the prior art, the erecting orassembling elements are located at spaced points along the edges of thebox. These fittings or elements must be made stout enough to withstandthe loads to which the structure is subjected. In our construction theinterlocking assembling means extend continuously around all edges ofthe box. Owing to this construction our box is tighter and more securethan are boxes of the prior art while at the same time being light.

It will be seen that we have accomplished the objects of our invention.We have provided an aircraft cargo box which is strong enough towithstand loads required for its use while at the same time being lightenough to meet maximum weight requirements of industry. Our aircraftcargo box can readily and expeditiously be assembled and knocked down.Parts thereof are replaceable and are interchangeable with others of ourcargo boxes. It can be stored in a relatively small space. Our cargo boxis watertight.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of ourclaims. It is further obvious that various changes may be made indetails within the scope of our claims without departing from the spiritof our invention. It is, therefore, to be understood that our inventionis not to be limited to the specific details shown and described.

Having thus described our invention, what we claim is:

We claim:

1. A cargo box including in combination a generally rectangular base,respective inwardly directed tongues extending along the sides of saidbase, a top having a central portion and a downwardly extendingperipheral portion providing an undersurface generally parallel to thesurface of said central portion, an inwardly directed tongue extendingaround the entire periphery of said downwardly extending portion, meansforming a channel in said undersurface above said tongue around theentire periphery of said top and a gasket in said channel, a pair ofsaid side panels each having a central portion and corner pieces carriedby said central portion, said corner pieces having at the edges thereofsurfaces generally parallel to the surface of said central portion, anoutwardly directed tongue extending along the upper edge of said paneland around the upper edge of said corner pieces, respective inwardlydirected tongues extending downwardly along the edges of said cornerpieces, an outwardly directed foot extending along the lower edge ofsaid panel, means forming a channel in the edge of said panel, saidchannel extending around the entire periphery of the side panel undersaid outwardly directed tongue and under inwardly directed tongues andinwardly of said foot and a gasket in said channel, respective endpanels, means providing an outwardly directed tongue extendingcontinuously along the top edge and down the side edges of said panel,an outwardly directed foot extending along the lower edge of said panel,means forming a channel in the edge of said panel, said channelextending around the entire periphery of said panel under said tongueand inboard of said foot and a gasket in said channel and a base, meansproviding respective inwardly directed tongues extending along the endedges and along the side edges of said base, said side panel and endpanel feet engaging said base tongues to urge the portions of said sidepanel and end panel gaskets running alongthe lower edges of the panelsinto engagement with said base, said inwardly directed side paneltongues engaging the portions of the outwardly directed end paneltongues running along the sides of the end panel to cause the end paneltongue portions to engage the side panel gaskets and to cause theinwardly directed side panel'tongues to engage the end panel gaskets,said outwardly directed side panel tongues and the portions of said endpanel tongues running along the top of said end panels engaging the toptongues so that said top tongue engages portions of said end panelgaskets and said side panel gaskets and said outwardly directed sidepanel tongues and said end panel tongue top portions engage said topgasket.

2. A cargo box including in combination, a generally rectangular base, apair of generally rectangular side panels, a pair of generallyrectangular end panels, and a generally rectangular top panel, firstreadily disengageable interlocking elements respectively unitary withand extending along the bottom edges of each of said side and end panelssubstantially from end to end thereof and unitary with and extendingaround the periphery of said base for connecting said side and endpanels to said base, second readily disengageable interlocking elementsrespectively unitary with and extending along the front and rear edgesof said side panels substantially from top to bottom thereof and unitarywith and extending along the side edges of said end panels substantiallyfrom top to bottom thereof for connecting said side panels to said endpanels and means connecting said top panel to said side and end panels,said second elements respectively comprising inwardly directed tonguesalong the end edges of said side panels and outwardly directed tonguesalong the side edges of said end panels.

3. A cargo box as in claim 2 in which each of said side panels and saidend panels and said top comprises generally channel shaped peripheralmembers formed of metal, a body of foamed synthetic resin surrounded bysaid members and skins of resin impregnated fibrous material.

4. A cargo box as in claim 2 in which each of said side panels comprisesa central portion and end pieces forming the corners of said box.

5. A cargo box as in claim 2 in which each of said side panels comprisesa central portion and respective corner pieces forming corners of saidbox, said corner pieces having at the edges thereof surfaces generallyparallel to the surface of said central portion, said top panelconnecting means comprising an outwardly directed tongue extending alongthe upper edge of said side panel throughout said central portion andaround said corners to points adjacent said corner piece surfaces, saidsecond element inwardly directed tongues extending along the edges ofsaid corner pieces at said surfaces.

6. A cargo box as in claim 2 in which each of said side panels comprisesa central portion and respective corner pieces forming corners of saidbox, said corner pieces having at the edges thereof surfaces generallyparallel to the surface of said central portion, said top panelconnecting means comprising an outwardly directed tongue extending alongthe upper edge of said side panel throughout said central portion andaround said corners to points adjacent said corner piece surfaces, saidsecond element inwardly directed tongues extending along the edges ofsaid comer pieces at said surfaces, each of said sides comprising meansforming a channel extending around the periphery thereof, said channelrunning along the upper edge of said. side panel under said outwardlydirected tongue and along the edges of said corner pieces under saidinwardly directed tongues and along the lower edge of said side panel,and a gasket disposed in said channel.

7. A cargo box as in claim 2 in which said first elements comprise meansforming an outwardly directed foot extending along the bottom of saidside and means forming a groove along the edge of said base forreceiving said foot.

8. A cargo box as in claim 2 in which said first elements comprise meansforming an outwardly directed foot extending along the bottom of saidside and means forming a groove along the edge of said basefor receivingsaid foot, means forming a channel in the bottom of said side inboard ofsaid foot, said channel extending along the length of said side and agasket in said channel for engaging the surface of said base.

9. A cargo box as in claim 2 in which said elements and top connectingmeans comprise outwardly directed tongues extending around the peripheryof said ends, means forming respective channels under said tongues and agasket disposed in said channels.

10. A cargo box as in claim 2 in which said ends are generallyrectangular whereby said channels have square corners, each of saidgaskets having obliquely cut ends at said corners and an adhesive forsecuring said out ends to each other to form mitered butt joints.

11. A cargo box as in claim 2 in which said top panel connecting meanscomprises a curved surface along an edge of said top and a pivoted hookat the top of one of said end panels.

12. A cargo box as in claim 2 in which said top panel connecting meanscomprises third readily releasable interlocking elements respectivelyunitary with and extending along the top edges of said side and endpanels substantially from end to end thereof and unitary with andextending around the periphery of said top to connect said top panel tosaid side and end panels.

13. A cargo box as in claim 2 in which said elements comprise pairs ofoppositely directed tongues, said tongues providing mating planesurfaces.

14. A cargo box as in claim 13 in which said tongues are generallywedge-shaped in cross section.

15. A cargo box as in claim 2 including gasketsrunning around theperipheries of said side panels and end panels and base for engagementby said elements to provide double watertight seals.

16. A cargo box as in claim 2 in which said elements comprise pairs ofoppositely directed mating tongues providing grooves, and gaskets insaid grooves for engagement by said tongues.

1. A cargo box including in combination a generally rectangular base,respective inwardly directed tongues extending along the sides of saidbase, a top having a central portion and a downwardly extendingperipheral portion providing an undersurface generally parallel to thesurface of said central portion, an inwardly directed tongue extendingaround the entire periphery of said downwardly extending portion, meansforming a channel in said undersurface above said tongue around theentire periphery of said top and a gasket in said channel, a pair ofsaid side panels each having a central portion and corner pieces carriedby said central portion, said corner pieces having at the edges thereofsurfaces generally parallel to the surface of said central portion, anoutwardly directed tongue extending along the upper edge of said paneland around the upper edge of said panel and around the upper edge ofsaid corner pieces, respective inwardly directed tongues extendingdownwardly along the edges of said corner pieces, an outwardly directedfoot extending along the lower edge of said panel, means forming achannel in the edge of said panel, said channel extending around theentire periphery of the side panel under said outwardly directed tongueand under inwardly directed tongues and inwardly of said foot and agasket in said channel, respective end panels, means providing anoutwardly directed tongue extending continuously along the top edge anddown the side edges of said panel, an outwardly directed foot extendingalong the lower edge of said panel, means forming a channel in the edgeof said panel, said channel extending around the entire periphery ofsaid panel under said tongue and inboard of said foot and a gasket insaid channel and a base, means providing respective inwardly directedtongues extending along the end edges and along the side edges of saidbase, said side panel and end panel feet engaging said base tongues tourge the portions of said side panel and end panel gaskets running alongthe lower edges of the panels into engagement with said base, saidinwardly directed side panel tongues engaging the portions of theoutwardly directed end panel tongues running along the sides of the endpanel to cause the end panel tongue portions to engage the side panelgaskets and to cause the inwardly directed side panel tongues to engagethe end panel gaskets, said outwardly directed side panel tongues andthe portions of said end panel tongues running along the top of said endpanels engaging the top tongues so that said top tongue engages portionsof said end panel gaskets and said side panel gaskets and said outwardlydirected side panel tongues and said end panel tongue top portionsengage said top gasket.
 2. A cargo box including in combination, agenerally rectangular base, a pair of generally rectangular side panels,a pair of generally rectangular side panels, a pair of generallyrectangular end panels, and a generally rectangular top panel, firstreadily disengageable interlocking elements respectively unitary withand extending along the bottom edges of each of said side and end panelssubstantially from end to end thereof and unitary with and extendingaround the periphery of said base for connecting said side and endpanels to said basE, second readily disengageable interlocking elementsrespectively unitary with and extending along the front and rear edgesof said side panels substantially from top to bottom thereof and unitarywith and extending along the side edges of said end panels substantiallyfrom top to bottom thereof for connecting said side panels to said endpanels and means connecting said top panel to said side and end panels,said second elements respectively comprising inwardly directed tonguesalong the end edges of said side panels and outwardly directed tonguesalong the side edges of said end panels.
 3. A cargo box as in claim 2 inwhich each of said side panels and said end panels and said topcomprises generally channel shaped peripheral members formed of metal, abody of foamed synthetic resin surrounded by said members and skins ofresin impregnated fibrous material.
 4. A cargo box as in claim 2 inwhich each of said side panels comprises a central portion and endpieces forming the corners of said box.
 5. A cargo box as in claim 2 inwhich each of said side panels comprises a central portion andrespective corner pieces forming corners of said box, said corner pieceshaving at the edges thereof surfaces generally parallel to the surfaceof said central portion, said top panel connecting means comprising anoutwardly directed tongue extending along the upper edge of said sidepanel throughout said central portion and around said corners to pointsadjacent said corner piece surfaces, said second element inwardlydirected tongues extending along the edges of said corner pieces at saidsurfaces.
 6. A cargo box as in claim 2 in which each of said side panelscomprises a central portion and respective corner pieces forming cornersof said box, said corner pieces having at the edges thereof surfacesgenerally parallel to the surface of said central portion, said toppanel connecting means comprising an outwardly directed tongue extendingalong the upper edge of said side panel throughout said central portionand around said corners to points adjacent said corner piece surfaces,said second element inwardly directed tongues extending along the edgesof said corner pieces at said surfaces, each of said sides comprisingmeans forming a channel extending around the periphery thereof, saidchannel running along the upper edge of said side panel under saidoutwardly directed tongue and along the edges of said corner piecesunder said inwardly directed tongues and along the lower edge of saidside panel, and a gasket disposed in said channel.
 7. A cargo box as inclaim 2 in which said first elements comprise means forming an outwardlydirected foot extending along the bottom of said side and means forminga groove along the edge of said base for receiving said foot.
 8. A cargobox as in claim 2 in which said first elements comprise means forming anoutwardly directed foot extending along the bottom of said side andmeans forming a groove along the edge of said base for receiving saidfoot, means forming a channel in the bottom of said side inboard of saidfoot, said channel extending along the length of said side and a gasketin said channel for engaging the surface of said base.
 9. A cargo box asin claim 2 in which said elements and top connecting means compriseoutwardly directed tongues extending around the periphery of said ends,means forming respective channels under said tongues and a gasketdisposed in said channels.
 10. A cargo box as in claim 2 in which saidends are generally rectangular whereby said channels have squarecorners, each of said gaskets having obliquely cut ends at said cornersand an adhesive for securing said cut ends to each other to form miteredbutt joints.
 11. A cargo box as in claim 2 in which said top panelconnecting means comprises a curved surface along an edge of said topand a pivoted hook at the top of one of said end panels.
 12. A cargo boxas in claim 2 in which said top panel connecting means coMprises thirdreadily releasable interlocking elements respectively unitary with andextending along the top edges of said side and end panels substantiallyfrom end to end thereof and unitary with and extending around theperiphery of said top to connect said top panel to said side and endpanels.
 13. A cargo box as in claim 2 in which said elements comprisepairs of oppositely directed tongues, said tongues providing matingplane surfaces.
 14. A cargo box as in claim 13 in which said tongues aregenerally wedge-shaped in cross section.
 15. A cargo box as in claim 2including gaskets running around the peripheries of said side panels andend panels and base for engagement by said elements to provide doublewatertight seals.
 16. A cargo box as in claim 2 in which said elementscomprise pairs of oppositely directed mating tongues providing grooves,and gaskets in said grooves for engagement by said tongues.